1. Field of the Invention
The present invention relates to a panel in a cathode ray tube, and more particularly, to a panel structure, which can secure an implosion proof characteristic by suppressing implosion caused by increased stress concentration at an upper portion of a panel coming from making the panel flatter during or after fabrication of the cathode ray tube.
2. Background of the Related Art
The cathode ray tube is a major component for displaying a picture in a display, such as a TV receiver or a computer monitor. FIG. 1 illustrates a side view with a partial cut away view of a related art color cathode ray tube.
Referring to FIG. 1, there is a fluorescent material screen 2 having red, green, and blue fluorescent materials coated thereon on an inside surface of the panel 1 fitted to a front face of the cathode ray tube, and a funnel 3 at a rear of the panel 1 welded to the panel 1, and an electron gun 4 in a neck portion 3a of the funnel 3. There is a shadow mask 6 fixed to a frame 7 near to the fluorescent material screen 2 inside of the panel 1 for selecting colors of electron beams 5 emitted from the electron gun 4. The frame 7 is hung from a sidewall of the panel 1 as support springs 8 fixed to the frame 7 are inserted in stud pins 9 fixed to the sidewall of the panel 1. There is an inner shield 10 fixed to one side of the frame 7 by fastening springs 11 for protecting the electron beams 5 traveling toward the fluorescent material screen 2 from external geomagnetism. There is a magnet 13 having a plurality of poles on an outer circumference of the neck portion 3a for correcting a traveling path of the electron beams 5 to hit onto a required fluorescent material exactly, and a reinforcing band 12 strapped around an outer circumference of the cathode ray tube for preventing implosion of the cathode ray tube caused by external impact during operation of the cathode ray tube. A structure of the panel 1 will be explained with reference to FIGS. 2 and 3. The panel 1 forms a front face of a vacuum container to maintain an inside space of the cathode ray tube in a vacuum for smooth traveling of the electron beams. FIG. 2 illustrates a section of key parts of a related art panel, showing a skirt part 28 bent backward from an effective surface portion 20.
Referring to FIG. 2, the panel 1 with the skirt part 28 has a fixed total height 27, with reference to which the skirt part 28 is divided into an upper part 22 inclusive of the effective surface part 20 having a radius of outward curvature divided by a mold match line 21, an intermediate part 24 from the mold match line 21 to a break line 23, and a lower part 26 from the break line 23 to the seal edge line 25. An edge of the effective surface part 20 in the upper part 22 transits to the skirt part 28 through curvatures R and Rxe2x80x2, bland curvatures, wherein the outside bland curvature Rxe2x80x2 is connected to the mold match line 21 at an upper part angle xe2x80x98axe2x80x99 of approx. 5xc2x0 to a vertical line, the intermediate part 24 has an intermediate part angle xe2x80x98bxe2x80x99 of approx. 1.5xc2x0 to the vertical line from the mold match line 21 to a break line 23, and the lower part 26 has a lower part angle xe2x80x98cxe2x80x99 of approx. 3xc2x0xcx9c4xc2x0 to a vertical line. Because the outward curved effective surface part of the related art panel, with a consequential curved fluorescent screen on the effective surface, distorts a picture on the fluorescent screen and provides a sensing quality, it is a trend that the effective surface of the panel is formed flatter, to increase a ratio of the height of the upper part greater.
In the meantime, referring to FIG. 3, the reinforcing band 32 strapped on an outside of the panel skirt part 28 is in general positioned starting from a boundary point of the bland curvature Rxe2x80x2 and the straight section of the upper part 22 of the skirt to entire intermediate part 24. The reinforcing band 32 has a section similar to a section of the panel skirt part 28, i.e., the reinforcing band 32 has a band body part 30 positioned at a lower part of the panel and a bent part 31 at the upper part 22 of the panel with reference to the mold match line 21 of the panel 1. The bent part 31 is bent at an angle identical to the angle xe2x80x98axe2x80x99 of the upper part of the panel, and the band body part 30 is parallel to a cathode ray tube axis. The reinforcing band compresses the panel 1 to act against expansion acting outward during evacuation of the cathode ray tube in fabrication, to reduce a stress on the panel, which makes the structure stable.
However, while the related art cathode ray tube with the curved screen surface exhibits a maximum tension at a periphery of the effective surface part of the panel as stress concentrates thereto, since the flat cathode ray tube with a thickness of the effective surface relatively greater than the related art cathode ray tube exhibits a tension stress concentrated to the skirt part of the panel which is relatively thin, that makes the flat cathode ray tube weak for the stress, such that the suggested panel form and the reinforcing band have a problem of lacking for an actual implosion proof requirement.
The problem can be described in detail as follows.
In the strapping of the reinforcing band, with an inner circumferential length shorter than an outer circumferential length on the mold match line of the panel, on the skirt part of the panel, to exert a contract force to the panel, that generates a tension on the reinforcing band in return, it is required to strap the reinforcing band more tightly on the skirt part for utilizing the tension fixed by a thickness, a width, and a yielding strength of the reinforcing band itself. However, the increased gap between the reinforcing band and the upper part of the skirt of the panel caused by the increased length of the bent part in the upper part of the reinforcing band coming from the increased ratio of the upper part of the panel in the course of making the effective surface flatter makes the tight contact difficult. That is, the increased panel upper part in the panel skirt part makes the contact between the panel upper part and the reinforcing band poor, to deteriorate implosion proof design efficiency. Moreover, the shifting of a tension center on the reinforcing band to front according to the increased panel upper part may cause slip when the reinforcing band slips off the panel.
Accordingly, the present invention is directed to an implosion proof panel in a cathode ray tube that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an implosion proof panel in a cathode ray tube, which can enhance an implosion proof characteristic.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings. To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, the implosion proof panel in a cathode ray tube, the cathode ray tube includes an effective surface part of a fluorescent screen formed on the panel, the panel with a substantially flat outside surface including, a skirt part starting from a periphery of the effective surface part to a seal edge line of the panel having an upper part, an intermediate part, and a lower part, the upper part and the intermediate part being divided by a mold match line, and a reinforcing band strapped around an outer circumference of the panel for preventing implosion of the cathode ray tube, wherein the panel meets the following conditions.
Rdo/(USDdxc3x971.75)xe2x89xa735, and 0.7xe2x89xa6(MMLHd/OAH)xe2x89xa60.9,
Where, Rdo denotes a radius of curvature of the outside surface of the panel in a diagonal direction, USDd denotes a length of the effective surface part of the panel in the diagonal direction, MMLHd denotes a height from the seal edge line to the mold match line of the panel, and OAH denotes a total height of the panel.
In another aspect of the present invention, there is provided an implosion proof panel in a cathode ray tube, the cathode ray tube including an effective surface part of a fluorescent screen formed on the panel, and the panel with a substantially flat outside surface including, a skirt part bent substantially at a right angle starting from a periphery of the effective surface part to a seal edge line of the panel through a mold match line, wherein the panel meets the following conditions.
Rdo/(USDdxc3x971.75)xe2x89xa735, and 0.5xe2x89xa6(MMLHu/CFT)xe2x89xa63.0,
Where, Rdo denotes a radius of curvature of the outside surface of the panel in a diagonal direction, USDd denotes a length of the effective surface part of the panel in the diagonal direction, MMLHU denotes a height from a center of the outside surface of the panel to the mold match line of the panel, and CFT denotes a thickness of the panel at the center.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.